The present invention relates to a golf club head, more particularly to an improved structure of the side portion of a hollow golf club head.
In recent years, there is a trend toward large-sized golf club heads. As a result of development of metal materials and improvements in the manufacturing techniques, wood-type hollow heads having a head volume of over 400 cc have been placed on the market.
In general, with the increase in the head volume, the height of the center of gravity is increased. In the case of large-sized golf club heads, therefore, it becomes necessary to relatively increase the weight in the sole portion in order to prevent the high center of gravity. However, in view of the swing balance and the like, the maximum weight of the head is limited. Accordingly, it is necessary to increase the margin of weight in other portions than the sole portion so that the weight can be increased in the sole portion.
If a lightweight fiber reinforced plastic is used in the crown portion, the weight margin can be increased in the crown portion. But, such a fiber reinforced plastic has a relatively large internal loss when compared with metal materials. Therefore, there is a tendency that the ball hit sound becomes dull. Further, there is a tendency that the hit feeling becomes bad since the response received by the player's hands at impact is reduced.